Re: [PATCH 2/2] [PATCH RFC v2 2/2] hyper-v: initialize Hyper-V CPUID leaves.

[Jan Kiszka <jan.kiszka@siemens.com>]

On 2011-10-23 17:39, Vadim Rozenfeld wrote:
> ---
>  target-i386/kvm.c |   73 +++++++++++++++++++++++++++++++++++++++++++++++++++-
>  1 files changed, 71 insertions(+), 2 deletions(-)
> 
> diff --git a/target-i386/kvm.c b/target-i386/kvm.c
> index 82fec8c..c061e3b 100644
> --- a/target-i386/kvm.c
> +++ b/target-i386/kvm.c
> @@ -29,6 +29,7 @@
>  #include "hw/pc.h"
>  #include "hw/apic.h"
>  #include "ioport.h"
> +#include "hyperv.h"
>  
>  //#define DEBUG_KVM
>  
> @@ -380,11 +381,16 @@ int kvm_arch_init_vcpu(CPUState *env)
>      cpuid_i = 0;
>  
>      /* Paravirtualization CPUIDs */
> -    memcpy(signature, "KVMKVMKVM\0\0\0", 12);
>      c = &cpuid_data.entries[cpuid_i++];
>      memset(c, 0, sizeof(*c));
>      c->function = KVM_CPUID_SIGNATURE;
> -    c->eax = 0;
> +    if (!hyperv_enabled()) {
> +        memcpy(signature, "KVMKVMKVM\0\0\0", 12);
> +        c->eax = 0;
> +    } else {
> +        memcpy(signature, "Microsoft Hv", 12);
> +        c->eax = HYPERV_CPUID_MIN;
> +    }
>      c->ebx = signature[0];
>      c->ecx = signature[1];
>      c->edx = signature[2];
> @@ -395,6 +401,54 @@ int kvm_arch_init_vcpu(CPUState *env)
>      c->eax = env->cpuid_kvm_features &
>          kvm_arch_get_supported_cpuid(s, KVM_CPUID_FEATURES, 0, R_EAX);
>  
> +    if (hyperv_enabled()) {
> +        memcpy(signature, "Hv#1\0\0\0\0\0\0\0\0", 12);
> +        c->eax = signature[0];
> +
> +        c = &cpuid_data.entries[cpuid_i++];
> +        memset(c, 0, sizeof(*c));
> +        c->function = HYPERV_CPUID_VERSION;
> +        c->eax = 0x00001bbc;
> +        c->ebx = 0x00060001;
> +
> +        c = &cpuid_data.entries[cpuid_i++];
> +        memset(c, 0, sizeof(*c));
> +        c->function = HYPERV_CPUID_FEATURES;
> +        if (hyperv_relaxed_timing_enabled()) {
> +            c->eax |= HV_X64_MSR_HYPERCALL_AVAILABLE;
> +        }
> +        if (hyperv_vapic_recommended()) {
> +            c->eax |= HV_X64_MSR_HYPERCALL_AVAILABLE;
> +            c->eax |= HV_X64_MSR_APIC_ACCESS_AVAILABLE;
> +        }
> +
> +        c = &cpuid_data.entries[cpuid_i++];
> +        memset(c, 0, sizeof(*c));
> +        c->function = HYPERV_CPUID_ENLIGHTMENT_INFO;
> +        if (hyperv_relaxed_timing_enabled()) {
> +            c->eax |= HV_X64_RELAXED_TIMING_RECOMMENDED;
> +        }
> +        if (hyperv_vapic_recommended()) {
> +            c->eax |= HV_X64_APIC_ACCESS_RECOMMENDED;
> +        }
> +        c->ebx = hyperv_get_spinlock_retries();
> +
> +        c = &cpuid_data.entries[cpuid_i++];
> +        memset(c, 0, sizeof(*c));
> +        c->function = HYPERV_CPUID_IMPLEMENT_LIMITS;
> +        c->eax = 0x40;
> +        c->ebx = 0x40;
> +
> +        c = &cpuid_data.entries[cpuid_i++];
> +        memset(c, 0, sizeof(*c));
> +        c->function = KVM_CPUID_SIGNATURE_NEXT;
> +        memcpy(signature, "KVMKVMKVM\0\0\0", 12);
> +        c->eax = 0;
> +        c->ebx = signature[0];
> +        c->ecx = signature[1];
> +        c->edx = signature[2];
> +    }
> +
>      has_msr_async_pf_en = c->eax & (1 << KVM_FEATURE_ASYNC_PF);
>  
>      cpu_x86_cpuid(env, 0, 0, &limit, &unused, &unused, &unused);
> @@ -953,6 +1007,13 @@ static int kvm_put_msrs(CPUState *env, int level)
>              kvm_msr_entry_set(&msrs[n++], MSR_KVM_ASYNC_PF_EN,
>                                env->async_pf_en_msr);
>          }
> +        if (hyperv_hypercall_available()) {
> +            kvm_msr_entry_set(&msrs[n++], HV_X64_MSR_GUEST_OS_ID, 0);
> +            kvm_msr_entry_set(&msrs[n++], HV_X64_MSR_HYPERCALL, 0);
> +        }
> +        if (hyperv_vapic_recommended()) {
> +            kvm_msr_entry_set(&msrs[n++], HV_X64_MSR_APIC_ASSIST_PAGE, 0);
> +        }
>      }
>      if (env->mcg_cap) {
>          int i;
> @@ -1190,6 +1251,14 @@ static int kvm_get_msrs(CPUState *env)
>          msrs[n++].index = MSR_KVM_ASYNC_PF_EN;
>      }
>  
> +    if (hyperv_hypercall_available()) {
> +        msrs[n++].index = HV_X64_MSR_GUEST_OS_ID;
> +        msrs[n++].index = HV_X64_MSR_HYPERCALL;
> +    }
> +    if (hyperv_vapic_recommended()) {
> +        msrs[n++].index = HV_X64_MSR_APIC_ASSIST_PAGE;
> +    }
> +
>      if (env->mcg_cap) {
>          msrs[n++].index = MSR_MCG_STATUS;
>          msrs[n++].index = MSR_MCG_CTL;

Not sure if we discussed this already: Is there no need to save/restore
the HV MSR values in the vcpu structure? Specifcially kvm_get_msrs looks
fishy as you request to read the state from the kernel but then simply
ignore it.

Jan

-- 
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux